Goodwill and Other Intangible Assets (Schedule of Other Intangible Assets) (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Finite-Lived Intangible Assets [Line Items]
Gross Intangible Assets	$ 13,580	$ 14,043
Accumulated Amortization	(9,931)	(8,970)
Net Intangible Assets	3,649	5,073
Core Deposits [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Intangible Assets	9,300	9,300
Accumulated Amortization	(6,341)	(5,256)
Net Intangible Assets	2,959	4,044
Customer Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Intangible Assets	4,206	4,669
Accumulated Amortization	(3,534)	(3,683)
Net Intangible Assets	672	986
Noncompete Agreements [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Intangible Assets	74	74
Accumulated Amortization	(56)	(31)
Net Intangible Assets	$ 18	$ 43